1. Field of the Invention
The present invention relates to a keyboard-type tone plate percussion instrument in which a musical tone is sounded by a tone plate being struck by a percussion unit in response to a key depression operation.
2. Description of the Related Art
Conventionally, percussion instruments such as keyboard-type tone plate percussion instruments have been known, in which percussion units such as hammer actions are provided so as to correspond to respective ones of sounding members such as tone plates, and a musical tone of a specific tone pitch is generated when a corresponding sounding member is struck by a corresponding percussion unit in response to a key depression operation. In these percussion instruments for producing a musical tone by a struck sounding member, it is also known to make tone color variable (Japanese Laid-open Patent Publication No. H05-127666).
In such percussion instruments, each hammer is provided with a plurality of heads having different hardness. These hammer heads are juxtaposed in a direction perpendicular to the longitudinal axis of a corresponding tone rod, and each hammer is made movable relative to the tone rod. With a hammer motion, a desired one of the hammer heads is selected for actually striking the tone rod. A tone color sounded from the tone rod struck by the hammer varies depending on which one of the hammer heads is selected.
With the percussion instrument disclosed in Japanese Laid-open Patent Publication No. 5-127666, however, a plurality of small-sized heads must be embedded in each hammer that is narrow in width. Thus, the hammer is complicated in construction and difficult to fabricate. To ensure an appropriate hammer head selection, the respective heads must be embedded in the hammer with high accuracy and the hammer must be moved relative to the tone rod with accuracy.
In some acoustic pianos, there are provided muffler felts each of which is disposed for insertion and extraction into and from between a corresponding pair of string and hammer. When a key is depressed with a corresponding muffler felt interposed between the string and the hammer, the string is struck by the hammer via the muffler felt. In these pianos, however, the muffler felts are made of the same material as that of hammer felts for the hammers. In other words, the muffler felts are provided with the intention of solely reducing sound volume but without the intention of changing tone colors.